We've stumbled across two hotfixes for the AT&T Tilt 2 and Pure. The first fix addresses inconsistent caller id functions and the second where the Windows phone freezes in the SMS application.
Both fixes are not ROM updates and will not cause you to lose your data. HTC notes that these fixes will survive a hard reset and will only need to be installed once. Do note that the fixes might not load if you're running a custom ROM. Stock AT&T only, it looks like.
The fixes for the Tilt 2 can be found here and for the Pure here. It appears that these issues are present only in the AT&T models so Sprint, Verizon and T-Mobile users need not worry.